A-12 The Dimensionality of Symptoms Before and After Sport-Related Concussion

Abstract

Abstract Objective Multiple factor analyses have examined the dimensionality of physical, emotional, and cognitive symptoms both before and after a sport-related concussion. The current study compared model fit and measurement invariance of five candidate factor models, including a one-factor model, original four-factor model (cognitive-sensory, vestibular-somatic, sleep-arousal, and affective), alternative four-factor model (cognitive, physical, sleep-arousal, and affective), five-factor model (cognitive-sensory separated), and bifactor model. Method Student athletes (N = 1,554; 56.7% boys; age: M = 16.1 ± 1.2) completed the Post-Concussion Symptoms Scale (PCSS) at preseason baseline and after a suspected concussion. Confirmatory factor analyses were conducted at both time points, with pre-injury to post-injury measurement invariance models (configural, weak, strong, and strict) also examined. Model results were assessed via fit indices (CFI ≥ .90/RMSEA≤.08) and change-in-fit indices (∆CFI ≤ -.01). Results All models other than the one-factor model showed excellent fit before and after concussion (CFIs>.95/RMSEAs < .06). Based on pre-injury to post-injury invariance analyses, full weak invariance was established for both four-factor and the bifactor models, and partial strict invariance was established for each of these models following modifications. Conclusions Support for partial strict invariance indicates that meaningful comparisons can be made between factor means before and after concussion for the four-factor and bifactor models, evidencing the validity of a total symptom score and specific symptom subscales before and after concussion. The alternative four-factor model may offer an improved conceptual framework compared to the original four-factor model, which included a non-intuitive cognitive-sensory factor. These findings could support the development of normative scores for PCSS subscales for use in research and clinical practice.